Molar Mass of Elements
What are the units of molar mass?
grams per mole (g/mol)
What is the molar mass of water (H2O)?
(2 * 1.01 g/mol) + 16.00 g/mol = 18.02 g/mol
How many moles are in 15 grams of magnesium (Mg)?
15 g / 24.31 g/mol = 0.62 mol
How many grams are there in 1 mole of bromine (Br)?
79.90 grams
You have 3 solutions of varying concentrations of sugar water: 1 M, 3 M, and 7 M. Which is the MOST concentrated?
Bonus: Which would taste the sweetest?
7 M is most concentrated and would taste the sweetest (highest ratio of sugar to water)
What is the molar mass of tin (Sn; atomic number 50)?
118.71 g/mol
What is the molar mass of table salt (NaCl)?
22.99 g/mol + 35.45 g/mol = 58.44 g/mol
I have 100 g of carbon dioxide (MM: 44.01 g/mol). How many moles do I have?
100 g / 44.01 g/mol = 2.27 mol
How heavy would 3 moles of silver (Ag) be?
3 mol * 107.87 g/mol = 323.61 grams
You add 0.5 moles of NaCl to 1.5 L of water. What is the molarity?
M = 0.5 mol / 1.5 L
M = 0.33 mol/L
What is the molar mass of copper (Cu; atomic number 29)?
63.55 g/mol
What is the molar mass of glucose (C6H12O6)?
(6*12.01 g/mol) + (12*1.01 g/mol) + (6*16.oo g/mol) = 180.2 g/mol
Convert 3 g of gold (Au) to moles.
3 g / 196.97 g/mol = 0.015 mol
Convert 15 moles of MgCl2 (MM: 95.21 g/mol) to grams.
15 mol * 95.21 g/mol = 1428.15 grams
You add 5 moles of NaCl to 1000 L of water. What is the molarity?
M = 5 mol / 1000 L
M = 0.005 M
Which element has a molar mass of 28.09 g/mol?
Silicon (Si)
What is the molar mass of ammonium sulfate (NH4)2SO4?
2*(14.01 g/mol + (4*1.01 g/mol)) + 32.06 g/mol + (4*16.00 g/mol) = 132.14 g/mol
A standard carton of milk contains 0.3 g of calcium. How many moles of calcium are you consuming when you drink a carton of milk?
0.3 g / 40.08 g/mol = 0.0075 mol
What is the mass of 12 moles of hydrochloric acid (HCl)?
12 mol * (1.01 g/mol + 35.45 g/mol) = 437.52 grams
You want to fill a 2 L pitcher with Kool-Aid at a concentration of 3.5 M. How many moles of Kool-Aid powder should you add?
3.5 mol/L * 2 L = 7 moles Kool-Aid powder
If you had 1 mole of iron (Fe) and 1 mole of gallium (Ga), which would be heavier?
Gallium (Ga; MM of 69.72 g/mol)
Oh no! You spilled an unlabeled acid and need to figure out its formula to know how to clean it! You know its molar mass is 98.1 g/mol and the start of its formula is H2SO_. What is the missing number of oxygens?
(2*1.01 g/mol) + 32.06 g/mol + (x*16.00 g/mol) = 98.1 g/mol
x = 4 oxygens
The acid is sulfuric acid, H2SO4
How many moles are in 38 g of potassium iodide (KI)?
38 g / (39.10 g/mol + 126.90 g/mol) = 0.23 mol
You weight out 3 moles of a substance and it weighs 505.08 grams. What is the molar mass of your substance?
3 mol * x = 505.08 g
x = 505.08 g / 3 mol = 168.36 g/mol
(The compound is cesium chloride; CsCl)
You want to make a 5 M solution of salt water. You have 1.5 L of water. How many grams of salt (NaCl; MM of 58.44 g/mol) should you add?
3 mol/L * 1.5 L = 4.5 mol NaCl
4.5 mol * 58.44 g/mol = 262.98 grams NaCl